This book presents the cost effective methods for designing a rectangular micro-strip patch antenna. In the recent years the development in communication system requires the development of low cost, minimal weight, low profile antennas that are capable of maintaining high performance over a wide spectrum of frequencies. This technological trend has focused much effort into the design of a rectangular micro-strip patch antenna. In this book, the performance in terms of directivity, radiation efficiency, return loss and radiation pattern of a rectangular micro-strip patch antenna have been analyzed and studied at 3 GHz.
Unwanted vibration in machine is one of the main problems as it affects the quality of the machined parts, tool life and noise during machining operation. Therefore the present work concentrates and aims on study of different controllable parameter that affect the responses like vibration amplitude and roughness of machined part. The part to be machined is kept on sandwich of plates made up Secondary Bed Material (SBM). The parameters that can easily be controlled are feed, RPM of cutter, depth of cut, and number of plates that form the secondary bed material. Polymers like PVC, PP plates and composites like Glass Fiber Epoxy (GFE) plates are used as SBM on which work-piece (MS Plate) was mounted by proper arrangement. Common up-milling operation was carried out in controlled manner. Vibration signals were recorded on the screen of oscilloscope and surface roughness of machined plate was found from the Talysurf. Finite element analysis (FEA) was carried out to know the resonance frequencies and it also lead to set some of the steps of precautions during the experimentation. Response surface methodology (RSM) approach is used to develop the model equation for each set of SBM.
Mechanical Vibration is the study of oscillatory motions of mechanical system. It is both useful and harmful for engineering systems. Sometimes, it is profitably used in musical instruments, propagation of sound etc. On the other hand, excessive vibration causes damage to buildings and rapid wear of machine parts such as gear & bearing. At the stage of resonance, it may even lead to the shutdown of the turbine units which directly disturbed the economical system, time management, employment system of a nation. Resonance is the stage where the natural frequency of the system is equal to the external excitation frequency. Due to this, the amplitude of vibration is excessive at resonance. So, determination of first few modes of natural frequency of a system is a must for design point of view. So, it is essentially required to have the knowledge of vibration (natural frequency) for a designer.
Mechanical vibration is normally an undesired condition which can cause problems such as discomfort, noise, fatigue, etc. Shock is a particular type of vibration of transient nature containing high levels of energy in a very short period of time It is vital for engineers to understand and apply vibration control methods, either by introducing structural modifications, reducing the source of vibration, or interposing an isolator between receiver and source. The easiest mathematical representation of these isolators is a passive combination of a spring and a damping of fixed properties. There are some isolators where the properties can change depending upon the vibration source called semi active, or adaptive vibration isolators. This book explores the application of a novel stiffness switching strategy to achieve an improved shock isolator. This is a two stage strategy controlling the vibration response during the shock and the later residual vibration. The book presents a review of the state of the art in shock isolation, theoretical models for switching stiffness and experimental validation.